I am facing a rather hard to learn problem in Mathematica: settingmultiple parameters simultaneously.

The basic problem is as follows: I have a set of parameters that define aphysical element (in my case an optical fiber). There are some standardfibers with fixed parameters.I wish to have a drop down menu (PopUpMenu in Math 8.0 I believe) thatsets these parameters to fixed values and have a few other parameters thatare adjustable in my simulation.

Ideally I wish to have all parameters to be able to be set usingManipulate or some other sort of way (input string) and have drop downmenus that make these variables "jump" to the defined value.

My questions are:

-how can I implement this selection-type menu with fixed parameter sets and-how can I have those parameters be adjustable alongside the above method?